S. enterica subspecies I contains over 1500 different serovars with an extraordinary diversity of host ranges and pathogenic mechanisms. This continuing project will generate a resource of sequenced genomes and corresponding phenotypic data of judiciously chosen S. enterica serovars to capture some of this diversity. In the previous funding period, reductions in sequencing costs allowed us to completely sequence three Enterobacterial genomes instead of the two originally proposed. A recent leap in sequencing technology will allow the near complete sequencing of an additional 25 S. enterica genomes at the same cost. Strains will be picked for both their clinical and their taxonomic importance. Previous project results taught us that Salmonella subspecies I serovars typically share a backbone of about 90% of their -4500 chromosomal genes. The remaining 10% of each genome in these 25 strains may contain an additional 4000 new or considerably divergent genes, including prophage, some of which contain multiple embedded virulence genes. The genome sequences will permit unprecedented resolution in the study of accelerated evolution of surface markers, such as lipolysaccharide and fimbrial genes, and lateral gene transfer events. The project will also acquire data on host-range, virulence, and in vitro phenotypes for 96 strains, including each sequenced strain, to identify laboratory models to study these strains. Sequence, annotation, and phenotypic data from a large number of S. enterica strains will be made publicly available and will lay the groundwork to allow the study of mechanisms responsible for host range, pathogenic mechanism, the emergence of new variants, and will provide information that can be exploited for novel therapy development.